J". E, Marr—Tke Skiddaiv Slates. 129 



synclinals. As to the age of the older rocks we have no evidence. 

 They may be Cambrian, and some may be of even earlier date. The 

 Skiddaw Slate period was certainly not one of continual deposition. 

 Coarse detrital beds occur again and again. The Skiddaw Grit 

 north of Skiddaw is often conglomeratic, and' the included pebbles 

 are of very varied type. Another conglomerate occurs on the old 

 road from the Vale of St. John to Ulleswater, not far from Wolf 

 Crag. It contains pebbles of slate in a greenish-grey argillaceous 

 matrix. Many of these beds may prove fossiliferous, for they have 

 been little searched, special attention having been hitherto paid to 

 the Graptolitic rocks. I have obtained fragments of a large Trilo- 

 bite from the banded black slates, associated with red and green 

 slates, at the head of Hause Gill, north-east of Skiddaw. They may 

 belong to an Arenig Asaplius, but may be older, and the locality 

 deserves careful examination, for Trilobite fragments also occur 

 in the green shales. Most of the Trilobites figured by Messrs. 

 Goodchild and Postlethwaite ^ appear to be Arenig forms, but some 

 may be older. 



A few words may be said concerning Mr. Ward's divisions of 

 the Skiddaw Slates. In his paper " On the Physical History of 

 the English Lake District," he places the beds below the " Skiddaw 

 Grit" in the Tremadoc Slates and Lingula Flags, those above that 

 grit in the Arenig. The correlation of the very marked grit north 

 of Skiddaw, with the much greater thickness of flaggy grits south 

 of Skiddaw, the grits north-west of Bassenthwaite, and those near 

 Buttermere is open to doubt. Furthermore, an examination of the 

 map appended to his paper shows that, upon his interpretation, a 

 great synclinal on the east side of the fault ranging down Derwent- 

 water is brought against a great anticlinal to the west of that 

 fault, a thing which certainly occurs in the district on a small 

 scale, but which is difficult to imagine on so large a one. But 

 the greatest objection to his proposed classification is furnished by 

 the fossil evidence. According to his view, all the beds west of 

 Derweutwater and Bassenthwaite, between the band of " Skiddaw 

 Grit " north of Bassenthwaite and that north-east of Buttermere 

 should be Tremadoc Slates or Lingula Flags ; nevertheless, in this 

 tract are situated Barf, Outerside, the Whinlatter Pass, Whiteside 

 and other localities yielding abundance of Arenig fossils. 



An examination of the Skiddaw Slate series shows that it is a 

 group of deposits of great diversity of character, folded violently on 

 a large and small scale ; the uppermost beds, which are fossiliferous, 

 represent part of the Ti-emadoc and the whole of the Arenig Series 

 of North Wales. These beds are folded in boat-shaped synclines 

 amongst what is probably a very much greater thickness of older 

 rocks, the palaeontology of which is practically unknown. It yet 

 remains to discover the ages of these rocks, forming, perhaps, 

 the greater bulk of the Skiddaw Slate formation, and this is a task 

 which may well occupy the attention of local geologists for many 

 years to come. 



1 Proc. Geol. Assoc, vol. ix. No. 7. 



DECADE IT. — VOL I. — NO. III. 9 



